I am having issues with my ADI-8 Pro, and I hope someone can give me a clue to what is wrong with it.

I have connected via ADAT in/out to my RME HDSP 9632 ADAT in/out.
In Hammerfall DSP settings (software), I have set clock source to ADAT in, and ADAT in is showing “sync”.

However, I am having crackling noises on some channels, and the DIGITAL INPUT -> ADAT is flashing on the ADI-8.

I am suspecting that the sync is not working on the ADI-8 side, but not sure. Does blinking ADAT mean no sync/lock?
Also I read that a faulty power supply could be the issue.

I have tried different optical cables, but did not fix it.
I have also looked everywhere for a solution or similar topic, but found none.

I hope someone can give me a clue on how to fix this.

Thanks in advance. :-)